1. Technical Field
The invention relates to a method of manufacturing power semiconductor structure, and in particular the method of manufacturing the trench power semiconductor structure.
2. Description of Related Art
With the higher requirement of energy conservation, the higher energy conversion efficiency is needed. The requirement of the design specification becomes stricter day by day, and thus it is a big challenge to the designer of the power converter device. In order to meet this requirement, the power converter device in the high converter efficiency becomes more and more important, wherein the power metal-oxide-semiconductor field effect transistor (Power MOSFET) is one of the most widely used in the power converter devices.
In the traditional planar MOSFET, the current is flowing along with the base surface. On the other hand, in the trench MOSFET, the gate is set in the trench, and the channel position of the MOSFET is changed, so as to make the current of the MOSFET is flowing perpendicular to the base. Hereby, the size of the element is reduced, and the motivation of the element is promoted, so as to reduce the manufacturing cost. The process of manufacturing traditional trench MOSFET needs at least six masking processes (lithography processes), wherein two masking processes are utilized to form the source and the body. In the initial stage of element development, the cost of the masking process is very expensive. Besides, the time wasting and the error in the process of manufacturing MOSFET might also increase the manufacturing cost.
Nowadays, in the semiconductor market, the competition advantage of the price is very important, and thus, searching for a simple manufacturing method to reduce the complication of the process and promote the competition advantage of the price without affecting the efficiency of the element is an important issue in this technical field.